1. Field of the Invention
The present invention relates to a snowmobile including a pair of left and right skis on a front side of a vehicle body, steering the skis via a steering shaft disposed on a front of a saddle type seat, mounting an engine in a cowling that covers the front side of the vehicle body, and traveling by driving a crawler disposed on a rear side of the vehicle body, and an engine for snowmobile.
2. Description of the Related Art
Conventionally, there is known a snowmobile having an engine mounted thereon disposed by being inclined rearward with respect to a traveling direction of the snowmobile (for instance, refer to Patent Document 1). When the engine is inclined rearward, a gravity center of the engine shifts rearward, so that a gravity center position of the entire vehicle body and a gravity center position of the engine are close to each other, resulting that a driving stability during the steering can be improved.
Here, a structure of the snowmobile having the engine disposed by being inclined rearward will be briefly described with reference to FIG. 10. FIG. 10 is a side view of the conventional snowmobile. In FIG. 10, a forward (traveling direction) and a rearward of the snowmobile are respectively indicated by arrow Fr and arrow Rr.
The entire front side of a snowmobile 100 is covered by a cowling 101 (refer to dotted line shown in FIG. 10). In a space covered by the cowling 101, an engine room 102 surrounded by a plurality of frames is formed. In the engine room 102, an engine 103 is disposed by being inclined rearward as described above.
A fuel tank 104 is disposed behind the engine 103. Further, an occupant seat 105 is disposed behind the fuel tank 104. On the occupant seat 105, an occupant (refer to two-dot chain line shown in FIG. 10) who steers the snowmobile 100 is seated. On the lower side of the fuel tank 104 and the occupant seat 105, a track housing 106 is formed to be opened downward along the front and rear directions.
A crawler 107 is disposed on the lower side of the track housing 106. The crawler 107 is formed of a driving wheel, a coupled driving wheel, an intermediate wheel, and a track belt 111 circumscribed around the respective wheels. An output of the engine 103 is transmitted to the driving wheel via a CVT (Continuously Variable Transmission), which enables the track belt 111 to wind around the respective wheels.
Meanwhile, a pair of left and right steering skis 112 are provided in a steerable manner on the front of and below the engine 103. The steering skis 112 are connected to a steering handle 114 via a steering mechanism including a steering shaft 113. The steering shaft 113 is extended diagonally upward from the front side of the engine room 102 to the upper side of the engine room 102 while passing in front of the engine 103. On a tip of the upper side of the steering shaft 113, the steering handle 114 is disposed along a vehicle width direction. Further, on the front of the steering handle 114 and above the engine room 102, a headlight 115 (refer to dotted line shown in FIG. 10) is provided to illuminate in front of the snowmobile 100.
Meanwhile, if attention is paid to a periphery of the engine 103, on the front of a crankcase 116 of the engine 103, an oil filter 117 is disposed to protrude forward. Further, a starter motor 119 is disposed above the crankcase 116 of the engine 103 and behind a cylinder 118.
Note that in FIG. 10, a gravity center position Ge of the engine 103 (hereinafter, referred to as gravity center position of engine Ge) and a gravity center position Gc of the vehicle body when the occupant rides on the snowmobile 100 (hereinafter, referred to as gravity center position of vehicle body including occupant Gc) are indicated.
[Patent Document 1] Japanese Patent Application Laid-open No. 2005-2877
As described above, according to the conventional snowmobile 100, the engine 103 is disposed by being inclined rearward, so that as far as this point is concerned, the gravity center position of engine Ge can be shifted rearward as shown in FIG. 10.
However, in the conventional snowmobile 100, the fuel tank 104 is disposed behind the engine 103. Therefore, if the engine 103 is inclined rearward, the fuel tank 104 also has to be disposed by being moved rearward according thereto, and in accordance with this, the occupant seat 105 also has to be disposed rearward. Eventually, it is practically difficult to further reduce a distance between the gravity center position of engine Ge and the gravity center position of vehicle body including occupant Gc.
Further, a position at which the oil filter 117 is disposed also relates to a main cause why the distance between the gravity center position of engine Ge and the gravity center position of vehicle body including occupant Gc cannot be reduced. Specifically, since the oil filter 117 is disposed to protrude forward of the engine 103 as described above, other component parts have to be disposed so as not to interfere with the oil filter 117. Accordingly, the other component parts cannot be disposed close to the engine in order to avoid the interference with the oil filter 117, so that the gravity center position Ge of the engine being a heavy object and the gravity center position of vehicle body Gc are forced to be separated.
In addition, since the other components are disposed on the front of the oil filter 117, an exchange work of the oil filter 117 is not easy, which is a problem.
Further, a position at which the starter motor 119 is disposed also relates to the main cause why the distance between the gravity center position of engine Ge and the gravity center position of vehicle body including occupant Gc cannot be reduced. Specifically, since the starter motor 119 is disposed above the crankcase 116 of the engine 103 and behind the cylinder 118 as described above, other component parts have to be disposed so as not to interfere with the starter motor 119. Accordingly, the other component parts cannot be disposed close to the engine in order to avoid the interference with the starter motor 119, so that the gravity center position Ge of the engine being a heavy object and the gravity center position of vehicle body Gc are forced to be separated.
In addition, since the other component parts are disposed around the starter motor 119, maintenance of the starter motor is not easy, which is a problem.